If you're going to be in the Huntersville area, The Fitness Center at Birkdale has an indoor pool, lots of classes and machines and even child care.

Huntersville also has an aquatic center with indoor pool and outdoor kids play area. It's been a while since I've been over there, but I think they might have racquetball.

I have heard that the YMCA at the Baxter community development in Fort Mill, SC is really nice if you live near South Charlotte.

I second the YMCA at Baxter. I belong there and really like it. They have:

Heated indoor swimming pool
Outdoor swimming pool
Magnum weight equipment
Free weights
Exercise bikes
Treadmills
Stair climbers
Elliptical cross

Trainers
Gymnasium
Aerobics
Racquetball courts
Locker rooms
Free child watch

You can check their website at:
http://www.upymca.org/branches/ftmill/ftmill-branch.html